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Start the environment
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Investigate the target
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Web-24. Exploiting a Race Condition in Secure Bank
Mission
Secure Bank lets users spend a coin balance on shop prizes. If the balance check and the deduction happen as two separate steps, think about how the gap between them could be exploited.
Hints
Hint 1 Show
Check whether the balance check and deduction happen atomically
Hint 2 Show
Consider what happens if you send many requests nearly simultaneously
Hint 3 Show
Each request may independently pass the balance check before any deduction lands